The utilization of water-based metalworking lubricants and coolants has become well established in light- to medium-duty applications such as cutting and grinding. Such metalworking fluids include true solutions or "synthetic" fluids, "semi-synthetic" fluids which contain some mineral oil, and emulsions, generally referred to as soluble oils. Such fluids not only remove heat but also serve to inhibit corrosion, lubricate, reduce surface tension, provide extreme-pressure lubrication, and control bacterial growth.
With increasing environmental demands, relating both to use and disposal, emphasis has been placed on the use of synthetic fluids, thus avoiding the presence of mineral oils. Although many advances have been made in providing suitable synthetic fluids, there remains a need for improved anti-wear, lubrication and extreme-pressure performance. This need is especially felt where recent advances in machine tool design require higher feed and cutting speeds as well as higher pressures and temperatures. Improvements in synthetic fluids are also particularly needed in the heavy-duty metal shaping and forming operation such as broaching and drawing.
The older oil-based lubricant additives provided suitable anti-wear and extreme-pressure performance by the use of chlorinated paraffins or waxes in their formulations. Very limited success has been realized in incorporating chlorinated derivatives in the newer synthetic fluids. This has been generally reported in Lubrication Engineering, vol. 37, pp. 715-721 (1981) and in Journal of American Oil Chemists Society, vol. 62, pp. 125-127 (1985). One example is the use of chlorinated fatty acids which are rendered water-soluble by salt formation with an amine or alkanolamine, such as triethanolamine. However, such ionic products interact with other additive components as well as with the calcium and magnesium ions usually present in a commercial water stream.